Objective To investigate the possible signaling mechanisms by which recombinant human platelet-derived growth factor (rhPDGF) accelerated healing of cutaneous wound in diabetic rats. Methods Four full-thickness skin wounds were incised in the back of 26 male Wistar diabetic rats. The wounded rats were divided into 3 groups (7 or 8 rats each group). One group without treatment was used as a control, and the other 2 groups were treated with rhPDGF at a dose of 7.0 μg/cm2 wound or vehicle ( DMSO/0.9%NaCl, vol/vol 1:1) from 1 to 14 days. The wound healing was evaluated by the measurements of the wound volume and area. Immunofluorescent and immunohistochemical staining were used to examine the phosphorylation of extracellular signal-regulated kinase 1/2(ERK1/2) and the expression of proliferative cell nuclear antigen (PCNA), respectively. Results Granulation tissue appeared in the bed of wound after injury. The number of blood capillary buds and fibroblasts was greater in the rhPDGF-treated group than that in the other 2 groups. A lot of inflammatory cells infiltration and collagen deposition were observed in the wound. The wound-volume in the rhPDGF-treated group was smaller than that in control group ( P ＜ 0.05). The reepithelialization rate in rhPDGF-treated group was higher than that in the other 2 groups at 7 days after injury ( P ＜ 0.05). The expression of PCNA in reparative cells was higher in rhPDGF-treated group than in control group or vehicle-treated group at 3,7 days after injury( P ＜ 0.05). The phosphorylation of ERK1/2 was stronger in rhPDGF-treated group than that in control group or vehicle group at 7 and 14 days after injury( P ＜ 0.05). Conclusion These results suggest that rhPDGF accelerates wound healing and improves healing quality by increasing the phosphorylation of ERK1/2.

Objective To compare the clinical outcomes of posterior lumbar interbody fusion(PLIF) using simple cage alone fusion with pedicle screw fixation and autogenous bone grafting and cage fusion with pedicle screw fixation in adult spondylolisthesis. Methods From March 2003 to March 2004,Twenty-seven patients with lumbar spondylolisthesis were divided in two groups. In group A, 15 patients were treated by PLIF using simple cage alone fusion with pedicle screw fixation, including 4 males and 11 females, aging 53-68 years. Isthmic defects were located at L4 in 9 cases, at L5 in 6 cases. Four patients were smokers. The preoperative mean disc space height was 5.4±2.3 mm, the mean percentage of slip was 36.8%±7.2%. In group B, 12 patients were treated by PLIF using autogenous bone grafting and cage fusion with pedicle screw fixation, including 3 males and 9 females, aging 56 years. Isthmic defects were located at L4 in 8 cases, at L5 in 4 cases. Five patients were smokers. The preoperative mean disc space height was 5.7±2.5 mm, the mean percentage of slip was 37.8%±6.2%. Two groups were compared in the amount of blood loss, duration of hospitalization, back pain, radiating pain, fusion rate, the intervertebral disc space height, the postoperative degree of slip and the fusion rate. Results All patients were followed up for 24-38 months. The mean follow-up was 29(24-36) months in group A and 26(24-38) months in group B. There were no statistically significant differences in follow-up period, age,sex, the location of isthmic defects, smoking, the preoperative disc space height and the percentage of slip between two groups (P>0.05). There were no statistically significant differences in the amount of blood loss, the duration of hospitalization, the fusion time between two groups(P>0.05). But there were statistically significant differences in the back pain score, the radiating pain score and the fusion rate between two groups(P<0.05).The postoperative disc space height and the degree of slip of the last follow-up were 5.8±2.2 mm and 25.6%±7.2% in group A, 6.2±2.5 mm and 24.1%±7.4 % in group B, showing statistically significant difference (P<0.05). Conclusion The PLIF using autogenous bone grafting and cage fusion with pedicle screw fixations is more beneficial to improving the fusion rate and preventing long-term instabilities than simple cage alone fusion with pedicle screw fixation in adult spondylolisthesis.

Objective To study the effect of dexamethasone to protect flaps from an ischemia-reperfusion injury and elucidate its mechanism of regulating the death course of the neutrophils. Methods The rats were randomly divided into 3 groups.The vein of the rat was clamped for 8 h after the flap had formed. Group A: the normal flap; Group B: the saline control flap; Group C: the treatment flap with dexamethasone. The survival area of the flaps was measured at 7 days; the apoptotic and necrotic neutrophils,tumor necrosis factor α (TNF-α), and interleukin 10 (IL-10) concentrations were measured. Results The flap survival are as in Groups A and C were larger than those in Group B. The apoptotic neutrophils in Group B were fewer than those in Groups A and C on the 1st and 3rd days after operation; however, they were more in number in Group B than in groups A and C on the 6th day. The necrotic cells in Group B were more in number than those in Groups A and C. In Group B, the plasma TNF-α concentration reached the maximum level at 1 h,while the IL-10 level reached the lowest 3 h after the reperfusion. In Group C, the TNF-α concentration was lower than that in Group B and decreased dramatically at 6 h. The IL-10 concentration was the lowest at 1 h, and increased rapidly at 3 h.Thus,ischemia-reperfusion could injure the flaps, probably through the abnormal action of the neutrophils, such as the disordered secretion of the cytokines and abnormal death course of the neutrophils. Conclusion Dexamethasone can protect the flap from an ischemia-reperfusion injury by its regulation for the neutrophil function.

Objective To investigated the distribution of epidermal stem cells in rat full-thickness wound tissues during the wound healing process and to elucidate the roles of epidermal stem cells in wound repair in vivo. Methods Eighty circular full-thickness wounds were produced on both sides of the back in 20 male Wistar rats labeled with BrdU 60 days previously (4 wounds in each rat). BrdU, β1 integrin and keratin 19 (K19) were employed to determine the epidermal stem cells with SP immunohistochemical methods, and the epithelialization was determined with routine histological methods of HE staining on the 3rd, 7th, 14th, and 21st days after operation. Results No cells with positive immunostaining for β1 integrin, K19 and BrdU were found in granulation tissue of wound in both groups during the healing process. However, a few scattered β1 integrin and K19 positive cells were found within the stratum spinosum and stratum granulosum of the epidermis on the wound edges on the 3rd day post-injury. And these positive cells gradually became more and more in number, and mostly concentrated on the border of wound edges till the wounds healed. In addition, the number of positive cells for β1 integrin and K19 in the infected wounds was less than that in non-infected wounds. These positive cells for β1 integrin and K19 staining on the wound edge were also positively stained with BrdU in the cellular nuclei. Conclusion The above results indicate that ectopia of epidermal stem cells present a major function during wound epithelialization.

Objective To determine the safety of the fetal olfactory ensheathing cell(OEC) transplantation in patients with chronic spinal cord injury (SCI) by examination of the magnetic resonance imaging (MRI). Methods A prospective clinical study involving 16 patients with chronic SCI was designed to investigate the feasibility and biological safety of the fetal OEC transplantation in treatment of SCI. The olfactory bulbs from the 3-4-month-old aborted human fetuses following the strict ethical guidelines were harvested and trypsinized down to single fetal OEC. These cells were then cultured for 12-17 days and were prepared for a clinical use. From November 2001 to December 2002, 16 patients with chronic SCI were randomly enrolled. The patients suffered from SCI for 1.5-8 years (average 4.3 years) after the injury. The suspension (50 μl) containing about 1×106 fetal OECs was transplanted by an injection into the patients' spinal cords above and below the injury site. All the patients were assessed before the transplantation and were followed up with MRI for 29-42 months (average 38 mon) after the transplantation. Results No cell-related adverse effects were observed in any patient during the follow-up period. The follow-up with MRI did not reveal any development of optic glial tumor, tumor-like mass, new hemorrhage, edema, expanding cyst, new cyst formation, infection or disruption of the neural structure in the transplant site of all the patients. Conclusion This is the first clinical study demonstrating the long-term safety of the OEC therapy for SCI. The results indicate that our protocol is feasible and safe in treatment of patients with chronic SCI within 38 months after the injury. Although the size of the samples for our study was not big enough, the positive results of the study have encouraged us to make a further research in this field.

Objective To explore the influence factors for the functional improvement after the fetal olfactory ensheathing cell (OEC) transplantation for chronic spinal cord injury(SCI). Methods The olfactory bulbs were harvested and trypsinized down to single fetal OEC. They were cultured for 12-17 days prepared for use. From November 2001 to December 2003, a total of 300 patients volunteered for the fetal OEC transplantation, among whom 222 suffered from complete chronic SCI and 78 suffered from incomplete chronic SCI. The procedures were performed on the patients with a disease course ranging from 6 months to 31 years (average 3.1 years) after their injuries. The fetal OEC was transplanted by the form of injections into the spinal cord at the upper and lower ends of the injury site. All the patients were assessed by the ASIA standard before the transplantation and 2-8 weeks after the transplantation. The influence factors including age, sex, duration after the injury, and injury degrees and levels were compared with those in the functional improvement after fetal OEC transplantation. Results The partially-improved neurological functions assessed by the ASIA standard were indicated by the motor scores increasing from 39.1±20.6 to 45.9±20.3 (P<0.001), the light touch scores from 51.7±24.9 to 63.4±23.0 (P<0.001), and the pin prick scores from 53.0±24.2 to 65.3±22.7(P<0.001). There was no significant difference in the functional improvement of the motor, light touch, and pin brick when compared with the age, sex, duration after the injury, and the injury degrees and levels. The motor scores and light touch scores at the cervical level were higher than the scores at the thoracic level. Conclusion The fetal OEC transplantation can partially improve the neurological functions quickly in treatment of the chronic spinal cord injury. All the influence factors except the motor scores and light touch scores, which were higher at the cervical level than at thoracic level, have no impact on the functional improvement after the fetal OEC transplantation.

Objecttive To investigate the possibility of repairing articular cartilage defects with the mesenchymal stem cells (MSCs)- seeded type Ⅰ collagen-glycosaminoglycan(CG) matrices after being cultured with the chondrogenic differentiation medium.Methods The adherent population of MSCs from bone marrow of 10 adult dogs were expanded in number to the 3rd passage. MSCs were seeded into the dehydrothennal treatment (DHT) cross-linked CG matrices; 2 × 106 cells per 9-mm diameter samples were taken.Chondrogenic differentiation was achieved by the induction media for 3 weeks. Cell contractility was evaluated by the measuement of the cell-mediated contraction of the CG matrices with time in culture. The in vitro formation of the cartilage was assessed by an assay employing immunohistochemical identification of type Ⅱ collagen and by immunohistochemistry to demonstrate smooth muscle actin (SMA).The cells seededing CGs were implanted into cartilage defects of canine knee joints. Twelve weeks after surgery, the dogs were sacrificed and results were observed. Results There was significant contraction of the MSCs-seeded DHT cross-linked CG scaffolds cultured in the cartilage induction medium. After 21 days, the MSC-seeded DHT cross-linked matrices were contracted to 64.4% ± 0.3%; histologically, the pores were fotmd to be compressed and the contraction coupled with the newly synthesized matrix, transforming the MSCsseeded CG matrix into a solid tissue in most areas. The type Ⅱ collagen staining was positive. The SMA staining was positive when these MSCs were seeded and the contracted CGs were implanted into the cartilage defects of the canine knee joints to repair the cartilage defects. The function of the knee joints recovered and the solid cartilaginous tissue filled the cartilage defects. Conclusion The results demonstrates that MSCs grown in the CG matrices can produce a solid cartilaginous tissue containing type Ⅱ collagen after being cultured with the chondrogenic differentiation medium and implanted into cartilage defects. We hypothesize that the following steps can be performed in the chondrogenic process: ①MSCs express SMA, resulting in matrix contraction, thus achieving a required cell density (allowing the cells to operate in a necessary society); ②Cells interact to form a type Ⅱ collagen-containing extracellular matrix (and cartilaginous tissue); ④Other factors, such as an applied mechanical stress, may be required to form a mature cartilage with the normal architecture.

Objective　To investigate the effects of trace elements on the metabolism of extracellular matrix and explore the physiological and pathological mechanism of trauma. Methods　Based on the experimental and clinical data, it was studied that the action of trace elements in the metabolism of extracellular matrix in trauma repairing. Results　During wound healing, the trace elements were the components of many kinds of enzymes, carriers and proteins. They took part in the synthesis of hormones and vitamins as well as the transmission of information system. They activated many different kinds of enzymes and regulate the levels of free radicals. The trace elements had the complicated effects on the synthesis, decompose, deposition and reconstruction of collagen and other extracellular matrix. Conclusion　The trace elements play an important role in regulating the metabolism of extracellular matrix.

Objective　To investigate the repairing effect of transplantation of allogeneic fetal bone in combination with a covering cryopreserved periosteal allograft to bone defect. Methods　Twenty Long-eared white male rabbits were chosen as experimental model of bilateral 12 mm combined bony and periosteal radial defect. Cryopreserved allograft periosteum with allogeneic fetal bone were implanted in the left defect as experimental side and fetal bone was simply transplanted in the right defect as control side. Bone repair process in the two groups were compared by macroscopy, microscopy, roentgenograms and the contents of calcium and phosphate in the defect area at 2、4、8 and 12 weeks after transplantation. Results　There was significant statistic difference in the contents of calcium and phosphate between the experimental and control sides at 4、8 and 12 weeks after transplantation (P<0.05). With time passing by, the contents of calcium and phosphate have the increasing trends. In the experimental group, lamella bone was seen and medullary canal recanalized at 8 weeks postoperatively. The histological section showed the bone lacuna and lamella bone were formed. Conclusion　It suggests that allogeneic fetal bone in combination with a covering cryopreserved periosteal allograft can promote bone repair, and allogeneic fetal bone is excellent bone substitute.

Objective　To review the recent progress in the treatment of wrist disorder by limited intercarpal arthrodesis and the related experimental study. Methods　Recent original articles related to limited intercarpal arthrodesis, including clinical practice and experimental study, were extensively retrieved and carefully analyzed. Results　Limited intercarpal arthrodesis could relieve pain and stabilize the wrist joint with partial motion. Conclusion　 With suitable indication and well selected operation approach, the limited intercarpal arthrodesis should be the optimal surgical intervention than total carpal athrodesis in the treatment of wrist disorder.